In recent years, technological advances have made possible the convergence of widely different technologies, such as telephony, computer and cable technologies, wireline and wireless technologies, and so forth, into heterogeneous networks offering a variety of services. Interoperability between different communication entities of such networks, or even between different entities of a homogenous network (e.g., between two telephony devices, computer devices, etc.) is made possible by using certain standard or proprietary interface protocols between the devices. Examples of known protocols include, without limitation, H.323, IPDC, H.248, SNMP and CORBA. Generally, communication between any peer entities (i.e., sending and receiving devices) cannot occur unless both devices use the same interface protocol. Thus, if a receiving device uses a different interface protocol than a sending device (or perhaps a different software version of the same interface protocol), any message(s) sent from the sending device to the receiving device will not be recognized or understood, causing a loss of communication.
A problem that arises is that as new interface protocols are introduced into the network or as existing protocols are upgraded, the changes/upgrades are made independently, inevitably at different times in different peer devices. Moreover, any particular sending or receiving device—whether or not it has received a protocol change/upgrade—will generally use its most recent protocol exclusively without regard to the protocols used by other peer devices. Indeed, most devices do not know which protocol other peer devices are using. Consequently, when changes/upgrades occur in a communication device, there can be a significant period of time when communication is lost between that device and one or more peer devices; communication is not restored until the peer devices have been transitioned to the same protocol.
A related problem is that different communication devices of a communication network can be manufactured, serviced and maintained by different vendors, such that a coordinated schedule may not exist for performing timely protocol changes in multiple entities/devices. Consequently, service and maintenance personnel associated with a communication device undergoing a protocol change/upgrade may not know when other peer devices will be upgraded to the same protocol. The transition period may comprise several hours, days or weeks, depending on the type of change/upgrade, operational procedures, common practices and the like. Clearly, during such a prolonged and/or indefinite transition period, the inability for peer devices to communicate due to a protocol inconsistency may significantly affect services provided by the network. For example, an inconsistency in a call signaling/control protocol between two or more telephony devices may render the devices unable to set up or tear down voice calls.
Accordingly, there is a need for communication device(s) having inconsistent protocols, such as may result from changes/upgrades, to maintain communications during prolonged or indefinite transition periods.